Background/Objectives: Enhancement of cellular NAD⁺ mediated by NMN has emerged as a pivotal strategy in modulating the aging process. This study aimed to systematically investigate the anti-aging effects of NMN on human skin fibroblasts, focusing on how the former contributes to the improvement of cellular health and function. This study elucidated the molecular and functional mechanisms by which NMN contributes to the attenuation of skin aging. Methods: We performed extensive in vitro and transcriptomic analyses. Human skin fibroblasts were treated with NMN, and the induced biological responses were observed under oxidative stress/photo-aging models. Results: Transcriptome analysis revealed distinct gene expression patterns for NAD⁺ and its precursors (NMN, NR, and NAM), showing significant differences between NMN and other precursors (NR and NMN). NMN seemed to be significantly involved in cytokine and chemokine activity. It significantly elevated cellular NAD⁺ levels, activated sirtuin and autophagy pathways, and enhanced mitochondrial function, collectively maintaining cellular homeostasis under stress. Furthermore, it suppressed cellular senescence, promoted cell proliferation, supported extracellular matrix integrity, and accelerated wound healing. Conclusions: The study provided essential mechanistic evidence supporting the anti-aging effects of NMN in skin cells and addressed the current lack of scientific validation of NMN-based topical applications. The findings established a solid academic background for future translational research and the development of NMN-based therapeutics and cosmeceuticals.

Background: Senotherapeutics, agents targeting cellular senescence, have recently shown great promise in anti-aging applications by removing senescent cells or attenuating the senescence-associated secretory phenotype (SASP). Ginseng and its bioactive component, ginsenosides, are widely recognized in Asia for their anti-aging effects. In this study, we investigated the senotherapeutic effects of wild and cultivated ginseng, and ginsenosides on fibroblasts. Methods: Using a human dermal fibroblast cell line, we induced senescence via UV exposure and cultured the cells with ginseng extracts and ginsenosides. Senolytic effects were evaluated by flow cytometry quantifying apoptotic cells, and senomorphic effects were evaluated by measuring gene expression related to SASP. Results: Wild ginseng exhibited a stronger senolytic effect than cultivated ginseng. We then focused on ginsenosides unique to wild ginseng, namely C-Mc1 and C-O. We demonstrated that these two ginsenosides are senolytic agents that selectively target senescent cells modulating expression of BCL2 family. Moreover, these ginsenosides also alleviated paracrine senescence by suppressing SASP factors in senescent cells. Conclusion: Wild ginseng and its ginsenosides C-Mc1 and C-O are potential senotherapeutic agents that can prevent the accumulation of senescent cells and the spread of senescence into neighboring cells.

Several plant-derived metabolites that enhance plant resilience in response to biotic and abiotic stresses have been developed as senolytics after their apoptotic effects were discovered. Several ginsenosides have also been reported to exert apoptotic effects. We therefore hypothesized that ginsenosides from wild P. ginseng, which survives for long periods in harsh environments, may act as senolytics for skin longevity. The phytochemical characteristics of wild P. ginseng were investigated by LC–MS/MS-based comparison of 38 ginsenosides between cultivated and wild P. ginseng. Wild P. ginseng had a 2.7-fold higher total ginsenoside content in the underground parts. Intermediate ginsenoside metabolites, particularly ginsenoside C-Mc₁, were especially abundant and characteristic of wild P. ginseng. To isolate trace amounts of ginsenoside C-Mc₁, adventitious roots were mass-cultured from tissue segments of wild P. ginseng. The cultured roots were subjected to a four-step column chromatography procedure (HP-20, silica gel twice, and reversed-phase) to obtain both a crude saponin fraction and purified ginsenoside C-Mc₁. These were then combined to prepare a C-Mc₁-fortified ginsenoside preparation derived from wild ginseng adventitious roots, designated wild ginseng ginsenosides (WGGs), thereby increasing the level of the naturally occurring characteristic metabolite C-Mc₁. The senolytic activity of WGGs was evaluated in senescence-induced fibroblasts. While WGGs maintained apoptotic cell levels in normal fibroblasts at 8–9%, they increased apoptosis in senescent fibroblasts to 18.4–25.9%, corresponding to a 1.3–1.8 fold increase over the negative control (14.4%). This study delineates the ginsenoside profile of wild P. ginseng and suggests the potential of sustainably produced WGGs as senolytics for skin aging. Graphical abstract